Calculate the wavelength (in nm) of a photon emitted by a hydrogen atom when its electron drops from the n = 3 state to the n = 2 state.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

bcde is the incorrect answer it is a